Note that, as discussed in detail for the four-quark scattering amplitude
\(q \bar{q} \rightarrow Q\bar{Q}\)  in [1]}, [2]},
the complete and linearly independent set of D-dimensional basis structures must in general
be enlarged according to the perturbative order at which \(q \bar{q} \rightarrow Q\bar{Q}\) 
is computed, because the Dirac algebra is infinite-dimensional for non-integer dimensions.
At each perturbative order only a finite number of linearly independent Lorentz structures
can appear in an amplitude, as is evident from inspecting the corresponding Feynman diagrams
which is a set of finite elements. 
